PRUNING GUIDE

Pacific NorthwestDON’T: Trees should never, ever be topped. And shrubs should rarely be sheared (except real topiary and formal hedges). Stripping all of the side branches off of a mature pine or any other tree or shrub, is also a no-no. Stripping is not to be confused with selective thinning, which can also make shrubs and trees look open and airy.

DO: Prune to enhance a plant’s natural beauty; to make it seem less oppressive, tidier, cleaner; to reduce size somewhat, depending on the type of plant. Selective pruning will reduce the bulk of the plant and taking off a few lower limbs is okay.

How: The two types of pruning cuts are thinning and heading. A heading cut is basically cutting off the tip or end of a branch, twig, or stem. Heading creates bushi-ness. The next spring growth is stimulated at the tips of cut branches. Shearing, topping and pinching hedges are heading cuts. Good for hedges and chrysanthemums. Not too good for most shrubs and trees.

A thinning cut removes the branch back to another branch, trunk, stem, or to the ground. Most pruning consists of thinning cuts. It forces new growth in existing branches and spreads new growth more evenly throughout the plant. Thinning cuts will let light into the interior, allowing for green branches to cut to if you choose to reduce the size of your shrub. It stays “done” longer and looks natural.

• PRUNING BY HABIT Prune to enhance the plant’s natural shape or “habit”. Plants have one of three basic habits.

I. CANE GROWERS

Plants that renew themselves by sending up new branches called canes from the base. These are very tough plants—you can hardly hurt them.

• Stare at your shrub.

• Take out all dead wood. Always do this first.

• Take out some (1/3 to 1/8) of the biggest and oldest, as well as a few of the puniest canes, to the base.

Do this every year to keep the size controlled.

• Pick out a few of the worst canes that rub or cross each other, that look sick or go the wrong way

(that is, start at the outside, head back through the center and out the other side), and ugly branches

(usually too straight).

• Generally prune to open up the center.

• Tidy up the top with thinning cuts. Cut back anything hanging on the ground and

cut to a larger stem or the ground.

• Prune with vigor!

CANE GROWERS—Take out canes at base

THE BUDGET—A third of the foliage can be removed and size reduced by about one quarter

NCutting back of the tip

HEADING CUTS

WRONG

THINNING CUTS

Cut back to a branch, stem or to the ground

N

RIGHT

PlantAmnesty’s

Guide to Pruning

OP

NorthwestPacific Maritime List

Sunset–Western Climate

Zones 4–5

PlantAmnesty

PO Box 15377

Seattle, WA 98115-0377

206.783.9813

www.plantamnesty.org

PlantAmnesty

is a non-profit

organization dedicated

to promoting better

pruning and gardening.

For more information write

to PlantAmnesty and

ask for order blanks to be sent.

Topic include:

• Tree care

• How to plant a tree

• Repairing mal-pruned

trees or shrubs

• Other pruning

PlantAmnesty

PO Box 15377

Seattle, WA 98115-0377

206.783.9813

www.plantamnesty.org

• Before you finish, stand back and observe. If necessary, you may sparingly shorten some

branches on tree-like shrubs (not trees). Cut back to a side branch.

• HINTS & TIPS On many shrubs and trees, especially tree-likes, you want to fix things slowly over three-to-five years. Do some now, come back next year. “Wander, ponder; and prune,” the old saying goes. Pruners always stare at their shrubs, trying to locate unwanted branches, imagining their shrubs without this or that branch, seeing how it will grow next year—seeing what needs to be done. Much like a haircut, it’s easy to take it off, hard to put back on. Know when to quit. If a plant is really too big, you may want to move it, remove it (go ahead, be ruthless!) or renovate it (not dealt with here). But try real selective pruning first!

II. MOUNDS

Look like mounds and are medium-tough plants, often found in mass plantings. They have small leaves or supple branches. You usually just want to tidy them up or reduce their size. People like to shear these—don’t you! These are easiest to make and keep smaller. Locate the longest, most unruly branch. Grab the tip with your left hand. Follow the branch down into the interior of the plant with your right-hand pruners, and snip it off two inches to one foot below the general surface level of your shrub. Cut to a side branch or stem, if possible. Don’t look for the next closest branch that’s too long, but the next worst too long, too unruly branch in the area and cut it back. Do this all over your shrub until it looks miraculously tidy and shorter, but natural.

These shrubs often benefit from taking out some of the old stems/canes to their base. This opens up and renews the shrub. Any dead wood or weeds should also be removed.

III. TREE-LIKES

Best let to get big. Not to be pruned heavy-handedly. Good selective pruning can open them up and make them look less oppressive, can train branches around gutters and off of houses, and can bring more beauty out of your plant. These shrubs are the hardest to do. Never remove more than 1/8 total leaf surface in one year. It stresses them or it can cause a watersprout-rebound effect—ick! Tree-likes have stiffish branches that divide many times.

• Most tree-likes just need to have all of the dead wood taken out.

If you still want to do more:

• Take out true suckers (straight-up, skinny branches from the base and trunk of the shrub or tree).

• Take out any big crossing, rubbing branches and double leaders (two main top branches with a

narrow branch-crotch angle) on trees, if it stays within the pruning budget.

• Take back or remove any branches hanging on the ground, if only up 1/2”. Other lower branches

can be removed.

• Take out the worst of the smaller crossing, rubbing branches—choosing the healthiest

and best-placed branch to remain.

• Prune to shorten or completely remove the worst wrong-way branches that start from the outside of the shrub, and go the wrong way back into the center and

out the other side.

• Sometimes a side branch has a smaller branch that heads too far up into the next “layer”, or goes too

far down. You can cut some of these off to add more definition to your shrub’s branches.

• If you have two parallel branches rather close together, it may look better to remove one. If you,

have three parallel branches you may want to remove the center one. This will make things look nicer.

MOUNDS—cut unruly branches off inside plant

THE BUDGET—A third of the foliage can be removed and size reduced by about one quarter

THE BUDGET—90% thinning cuts—no size reduction— 1/8 to 1/16 foliage removed...Go easy!

TREES AND TREE-LIKES

DOUBLE LEADER

CROSSING

ON GROUND

WRONG WAY SUCKERS

PARALLEL BRANCHES

TOO FAR UP

SHORTEN SHRUBS ONLY 10%

TOO FAR DOWN

Pacific Maritime List Sunset – Western Climate Zones 4 – 5

HELPFUL LISTS

AcubaAbeliaBarberries (some canes)Box HoneysuckleBoxwoodBurning BushChoisya (Mexican Orange)EscalloniaEvergreen Azaleas

Evergreen Viburnums (somewhat tree-like as well)

Hollies Japanese HollyPotentillasRock RoseSnowberrySpiraeas

MOUNDS (GRAB & SNIP)

BambooBuddleia (Butterfly Bush)Deutzia ForsythiaHydrangeaKerria

Nandina (Heavenly Bamboo)Oregon GrapeRed-twig DogwoodRosesWeigelasWild Oregon Grape

CANE GROWERS (CUT CANES TO THE GROUND)

Deciduous AzaleasElderberryEnkianthus Huckleberries KalmiaLilac Manzanita Pieris (Andromeda)

RhodendronsSpindletreeViburnums: Leatherleaf Double-file Highbush Cranberry Winter Snowball

TREE-LIKES (THIN-OUT, MANY SMALL CUTS)

CherryCotoneaster CrabappleDogwoodFig

Filbert (Hazelnut)HamamelisMagnoliaParrotiaPlum

Water sprouts easily, therefore thin lightly

CamelliasLaurelMature RhododendronsPhotinia

PierisPineStrawberry Tree

Takes heavy thinning or arborizing

LaurelPhotiniaPrivet

PyracanthaYew

Tough Tree-Likes (Can be headed into hedges or let go natural)